Consulting

Zick Technologies can be called upon for expert assistance in any area related to the modeling of petroleum thermodynamics and phase behavior. In business since 1993, but with industry experience dating to 1983, we are uniquely qualified to provide advice, guidance, analysis, design, and engineering solutions of all levels in the following areas of specialization (to name a few).

Fluid Characterization

No one does a better job of developing equation-of-state (EOS) petroleum fluid characterizations. One of the main reasons for that is PhazeComp. This state-of-the-art PVT software was developed by Zick Technologies specifically for fluid characterization work. Fluid characterization expertise is essential to writing the industry’s best PVT program, and having the best PVT program is essential to doing the best fluid characterization work. No one has better fluid characterization software than PhazeComp, and no one knows how to use it better than Zick Technologies. Because of PhazeComp’s unparalleled features, here are some of the characterization issues that are addressed in unparalleled fashion:

Any number of EOS fluid characterizations (reservoir, surface, reduced-component, e.g.) can be developed (tuned) simultaneously.

Black-oil characterizations can also be developed along with the EOS characterizations, using arbitrarily complicated, user-defined surface processes to define the gas-oil separations.

Proprietary techniques for component splitting and pseudoization allow for easy, accurate, and automated conversions between characterizations.

Any number of fluid samples (each with its own characterization, if desired) can be included.

Fluid samples can be mathematically decontaminated of oil-based drilling mud.

Any number of experiments, of any type (including non-standard, user-defined), can be included.

Output streams from any experiment (or other calculation) can be used as input for subsequent experiments (calculations).

Any number of user-defined variables can be used to tune the characterizations (often in amazingly clever ways).

Minimum miscibility pressures and enrichments can be calculated (rigorously).

Gravitational segregation can be calculated by thermodynamic equilibrium, or with a proprietary damping factor that offers control over the compositional gradients while still maintaining hydrostatic equilibrium.

Any data that can be measured (even theoretically) can be used in the tuning process, including miscibility and gravitational segregation data.

All phase behavior calculations can be checked for the existence of three-phase equilibria, which wreak havoc on reservoir simulations. Once identified, three-phase solutions can usually be eliminated.

Parameter consistency (from property to property and component to component) is always maintained, eliminating phase behavior anomalies that are often predicted by EOS characterizations developed with other, less consistent, methods.

PVT Experiment Design

The best fluid characterizations are developed from good quality PVT data of the appropriate types. This is especially true when a fluid characterization is to be used for the modeling of miscible gas flooding or other enhanced oil recovery processes. We can recommend and help design the PVT experiments that will produce the best data for such purposes.

Fluid Characterization Evaluation

Equation-of-state fluid characterizations involve dozens of potentially adjustable parameters. It is all too easy (and common, unfortunately) for characterizations to be built with inconsistent or nonphysical parameters. Such characterizations will usually result in untrustworthy phase behavior predictions. We can evaluate existing EOS characterizations for questionable parameters and anomalous predictions. In case of problems, we can recommend corrections. Of course, characterizations developed by Zick Technologies will avoid such problems from the start.

Multiphase Screening

Equation-of-state characterizations of some oils tend to predict three-phase equilibria under certain circumstances, particularly at low temperatures or during gas injection processes, especially when carbon dioxide is involved. These predictions may or may not be physically realistic. In any event, they are highly undesirable for reservoir simulation purposes. Most simulators are designed only for two-phase equilibria. Three-phase equilibria present themselves as multiple two-phase solutions, which can produce oscillatory results and send a simulator into non-convergent loops, time-step cuts, and eventual failure. With PhazeComp, however, a characterization can be checked for possible three-phase equilibria within the expected range of reservoir conditions, even those produced during a dynamic gas injection process. If three-phase equilibria are detected, they can usually be eliminated by judicious adjustments to the characterization (often with little or no significant loss of accuracy). Zick Technologies can help with any of these procedures, from screening to correction.

Miscibility Predictions

Under the right conditions, oil displacements by gas injection can exhibit highly efficient, multi-contact, developed miscibility. In the laboratory, minimum miscibility pressures (MMPs) and minimum miscibility enrichments (MMEs) can be determined by slimtube displacement experiments. With an equation of state, MMPs and MMEs can be estimated by slimtube simulations. Zick Technologies can perform slimtube simulations, if requested, but they are quite time-consuming and difficult to interpret with any consistency. Fortunately, there’s a better alternative. PhazeComp includes proprietary methods for estimating MMPs and MMEs directly. The algorithms mimic the physics of slimtube displacements, but assess the miscibility itself. Typically, PhazeComp’s MMP and MME calculations are about two orders of magnitude more efficient than those of traditional slimtube simulations, with results that are not only accurate, but also consistent enough to be differentiated or correlated (with respect to temperature, composition, etc.). PhazeComp users can make these miscibility calculations themselves, but Zick Technologies would also be glad to help.

Mathematical Decontamination

We can estimate in-situ reservoir fluid compositions for samples that have been contaminated by oil-based drilling mud. We assume a Gamma (not just exponential) distribution (with variable parameters) for the heavier components of the original fluid. Components in excess of the underlying distribution are then assumed to have been contributed by the mud.

Extended Compositional Analysis Correction

Fluid compositions that have been determined by gas chromotography are often extremely unreliable. They are heavily reliant on questionable correlations and calibrations that, unfortunately, not many laboratories apply appropriately. The usual result is that the reported amount of the heaviest, non-eluted fraction of the fluid can be grossly in error. We have developed techniques that can effectively correct for these errors. We use these techniques regularly when developing our EOS fluid characterizations, but they can also be applied independently.

Miscellaneous Equation-of-State Applications

Besides the EOS calculations already mentioned, Zick Technologies can perform almost any arbitrarily complicated sequence of EOS phase behavior calculations on a custom basis. In many cases, we can deliver PhazeComp or Streamz template files to perform such calculations repeatedly.

Custom Software

We have been applying computer programming skills and numerical analysis expertise to thermodynamics, computational fluid mechanics, and other difficult problems in science and engineering since 1974. We are always open to proposals for custom software projects in these areas.